Neelakantan P, et al. - The physicians designed this study to explore whether 1 type of contracted endodontic access cavities (orifice-directed dentin conservation [DDC] access) was able to debride the pulp chamber, root canals, and isthmus of mesial roots of mandibular molars similar to a traditional endodontic access cavity (TEC). In DDC, debridement of the pulp chamber was significantly compromised. The type of access cavity did not affect the amount of remaining pulp tissue (RPT) in the root canals and isthmus.